Natural food additives and methods of obtaining thereof

Abstract

The present disclosure relates to food additives of natural origin with improved texturizing and preservative properties, and to the method to obtain said food additives. Furthermore, the present disclosure relates to a composition, in particular a stable composition comprising said food additives.

Description

[0001] NATURAL FOOD ADDITIVES AND METHODS OF OBTAINING THEREOF

[0002] TECHNICAL FIELD

[0003] The present disclosure relates to food additives of natural origin with improved texturizing and preservative properties, as fruit flour, particularly nectarine, pear, apple and peach fruits, and to the method to obtain said food additives. Furthermore, the present disclosure relates to a composition, in particular a stable composition comprising fruit flour with improved functional, antimicrobial and antioxidant properties.

[0004] BACKGROUND

[0005] Food additives are fundamental to allow food industries to do food products meeting the increasing challenges of the market needs related with food enhancement, stability and preservation, avoiding food spoilage and alterations. Currently, natural food additives (NFA) are preferred to make food rather than synthetic once, because in addition to the fact that NFA can promote the same benefits to foods, while compliant with the EU regulations and consumer demands, searching for Clean Label ingredients and less processed foods. Moreover, the NFA have gained huge interest from consumers in opposition to the synthetic alternative that are found in the market, mainly related with health and well-being reasons, pushing the global food industry to sift for more natural final products, while searching for sustainable alternatives, thus, the incorporation of natural additives are suitable alternatives to solve this problem.

[0006] Food additives are divided into groups principally: i) preservatives, like antioxidants, antimicrobials, and antibrowning agents; ii) colorings, iii) flavorings including sweeteners, natural and synthetic flavors and flavor enhancers iv) texturizing divided into emulsifiers and stabilizers and finally v) nutritional additives and vi) miscellaneous agents. The benefits of NFA are numerous, their synergies and multipurpose applications are the remarkable features when compared to the synthetic additives that in most cases exhibit just one effect in the food. On the other hand, although most of the NFA are produced using the same methods for example extraction and purification from raw plants, vegetables, fruits or microorganisms or being enzymatically hydrolyzed or modified, there still a lack on the obtention of novel Clean Label NFA, by application of green-sustainable methodologies and coming from different renewable resources. In this matter, the upcycling of agro-industrial side streams like non-compliant fruits and their by-products represents suitable and renewable source of value to originate new value-added food additives with functional compounds and multi-functional properties, which will be beneficial to all the actors within the food supply chain. For instance, non-compliant fruit still contains great portions of organic acids, phenolic antioxidants, proteins, simple sugars and polysaccharides - dietary (insoluble and soluble) fiber, make them industrial sources with reduced cost and rich in natural compounds that can potentially be applied for upcycling process at the food industry as raw materials for the production of natural food additives.

[0007] By the nature composition of these NFA coming from non-compliant fruits, they can provide multiple beneficial properties: organoleptic, texture and functional, once they are incorporated into the food matrix, highlighting the substitution of sugar, preservatives, and colorants, while texture, viscosity and antioxidant capacity are also improved as well as the microbial stability.

[0008] These facts are disclosed in order to illustrate the technical problem addressed by the present disclosure. On the other hand, all food products are created and launched to withstand the consumer and market demands. In this matter, the food industries have been building efforts upon the development of final food products with functional properties due to present-day consumers are seeking to boost the beneficial properties of the foods that they normally purchase and consume every day. For instance, nectarine flour / powder ingredient could be used for the development of fiber-enriched products aimed at reducing the risk of chronic diseases, such as type 2 diabetes and cardiovascular conditions. Moreover, the increasing predominance of celiac disease and gluten sensitivity has further increased the demand for gluten-free flours. Traditional gluten-free flours made of maize or rice normally have deficiency in fiber, antioxidants and essential nutrients, which are eliminated during their refining process. The incorporation of fruit flour developed through tailored minimal processing techniques offers a solution to enhance the nutritional profile of gluten-free flours. Modern food industries are focusing on ingredients that can join functionality and bioactive benefits without altering their product's apparency and formulations by the application of these kinds of novel natural healthier alternatives.

[0009] The aim of the current invention is to provide a natural solution which is both nutritional and has bioactive properties, especially antioxidant and antimicrobial capacities. SUMMARY

[0010] The present disclosure relates to food additives of natural origin with improved texturizing and preservative properties, as fruit flour / powders, and to the method to obtain said food additives. Furthermore, the present disclosure relates to a composition, in particular a stable composition comprising fruit flour with improved antioxidant properties.

[0011] The invention thereto provides a fruit flour according to claim 1. The fruit flour obtained according to the invention is characterized by a reduced sugar content, thereby contributing to improved antimicrobial activity against food pathogens and enhanced preservative functionality. The flour further provides improved stability, natural coloring, and antioxidant activity, making it suitable for a wide range of uses in food, nutraceutical, and cosmetic applications.

[0012] In a preferred embodiment, said fruit flour is nectarine flour.

[0013] The current invention further provides a composition comprising the fruit flour according to claim 16.

[0014] The invention further provides the use of the fruit flour as a preservative agent, preferably as a food preservative agent, including antimicrobial activity against pathogens. Other uses include the use of the fruit flour according to claim 22 and 23, which respectively describe use as an antioxidant and as a food coloring agent.

[0015] According to claim 24, the invention further provides a method for producing a fruit flour, preferably a nectarine flour, comprising the steps of juicing fruits, separating pomace, pressing the pomace, drying to a moisture content below 5% by weight, milling, and sieving to obtain a flour of particle size equal to or less than 250 pm

[0016] FIGURES

[0017] Figure 1 shows the profile of the particle size distribution of nectarine flour. Figure 2 shows the mean values of the Water (WAC) and oil (OAC) absorption capacity of nectarine flour. All determinations were carried out in triplicated and mean value ± standard deviation.

[0018] Figure 3 shows the emulsifying capacity (EC) of nectarine flour. All determinations were carried out in triplicated and mean value ± standard deviation.

[0019] Figure 4 shows a color anlysis (CIE L*, a*, b* color values). All determinations were carried out by means of six replicates and mean value ± standard deviation.

[0020] Figure 5 shows concentrations of soluble sugars and organic acids identified and quanified in nectarine flour. All determinations were carried out in triplicated and mean value ± standard deviation.

[0021] Figure 6 shows the growth inhibition curves of Flour < 100, Flour 100-250 and nectarine powder against Salmonella enteritidis and Pseudomonas aeruginosa. Blue line: positive control (C+), dark blue line: 1% (w / v) orange line: 3% (w / v), green line 5% (w / v) and purple line: negative control (C-).

[0022] Figure 7 shows the growth inhibition curves of Flour < 100, Flour 100-250 and nectarine powder against Escherichia coll and Listeria monocytogenes. Blue line: positive control (C+), dark blue line: 1% (w / v) orange line: 3% (w / v), green line 5% (w / v) and purple line: negative control (C-).

[0023] Figure 8 shows the growth inhibition curves of Flour < 100, Flour 100-250 and nectarine powder against Staphylococcus aureus and Bacillus cereus. Blue line: positive control (C+), dark blue line: 1% (w / w) orange line: 3% (w / w), green line 5% (w / v) and purple line: negative control (C-).

[0024] DETAILED DESCRIPTION

[0025] The present invention describes natural flours that are suited for many applications in the food, beverage and cosmetic sector, because of their antimicrobial properties.

[0026] Unless otherwise defined, all terms used in disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By means of further guidance, term definitions are included to better appreciate the teaching of the present invention.

[0027] As used herein, the following terms have the following meanings:

[0028] "A", "an", and "the" as used herein refers to both singular and plural referents unless the context clearly dictates otherwise. By way of example, "a compartment" refers to one or more than one compartment.

[0029] "About" as used herein referring to a measurable value such as a parameter, an amount, a temporal duration, and the like, is meant to encompass variations of + / - 20% or less, preferably + / -10% or less, more preferably + / -5% or less, even more preferably + / -1% or less, and still more preferably + / -0.1% or less of and from the specified value, in so far such variations are appropriate to perform in the disclosed invention. However, it is to be understood that the value to which the modifier "about" refers is itself also specifically disclosed.

[0030] "Comprise", "comprising", and "comprises" and "comprised of" as used herein are synonymous with "include", "including", "includes" or "contain", "containing", "contains" and are inclusive or open-ended terms that specifies the presence of what follows e.g. component and do not exclude or preclude the presence of additional, non-recited components, features, element, members, steps, known in the art or disclosed therein.

[0031] Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order, unless specified. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

[0032] The recitation of numerical ranges by endpoints includes all numbers and fractions subsumed within that range, as well as the recited endpoints.

[0033] The expression "% by weight", "weight percent", "%wt" or "wt%", here and throughout the description unless otherwise defined, refers to the relative weight of the respective component based on the overall weight of the formulation. Whereas the terms "one or more" or "at least one", such as one or more or at least one member(s) of a group of members, is clear per se, by means of further exemplification, the term encompasses inter alia a reference to any one of said members, or to any two or more of said members, such as, e.g., any >3, >4, >5, >6 or >7 etc. of said members, and up to all said members.

[0034] Unless otherwise defined, all terms used in disclosing the invention, including technical and scientific terms, have the meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. By means of further guidance, definitions for the terms used in the description are included to better appreciate the teaching of the present invention. The terms or definitions used herein are provided solely to aid in the understanding of the invention.

[0035] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to a person skilled in the art from this disclosure, in one or more embodiments. Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0036] In a first aspect, the current invention discloses a fruit flour obtainable from fruits, said flour has a total sugar content less than 45 g / 100 g flour where said total sugar content is measured by the total sucrose, glucose and fructose content. Preferably, said total sugar content is measured by high-performance liquid chromatography (HPLC) with refractive index (RI) after aqueous extraction of the flour. Alternatively, enzymatic spectrophotometric assays for sucrose, glucose and fructose may be employed. The reduction of sugar content compared to conventional fruit-derived powders provides several advantages. A lower sugar content contributes to a reduced glycaemic impact of the flour and enables its use in health-conscious food products, diabetic-friendly formulations, and reduced-calorie diets. Furthermore, lower sugar levels improve microbiological stability, as sugars are a primary substrate for microbial growth; flours with less than 45 g / 100 g flour sugars therefore show enhanced shelf-life and reduced risk of spoilage. In addition, the lower sugar profile allows the flour to be used as a functional texturizing ingredient rather than as a sweetener, broadening its applications in both savoury and sweet food formulations. Preferably, the sucrose content is less than 22 g / 100 g flour, the glucose content less than 8 g / 100 g flour, and the fructose content less than 15 g / 100 g flour. Each of these sub-ranges contributes to the balanced nutritional profile of the flour. In particular, reducing fructose content is advantageous for addressing dietary concerns related to fructose malabsorption and metabolic health.

[0037] In an embodiment, said total sugar content is less than 40 g / 100 g flour. In an embodiment, the total sugar content is less than 35 g / 100 g flour, less than 30 g / 100 g flour, less than 25 g / 100 g flour, or even less than 20 g / 100 g flour. In an embodiment, the total sugar content is between 1 and 45 g / 100 g flour, preferably between 1 and 40 g / 100 g flour, more preferably between 1 and 35 g / 100 g flour, and most preferably between 5 and 35 g / 100 g flour or between 10 and 30 g / 100 g flour. The total sugar content may be measured by high-performance liquid chromatography (HPLC) with refractive index detection after aqueous extraction, or by enzymatic spectrophotometric assays for sucrose, glucose and fructose. Lower total sugar content is advantageous because it reduces the caloric load of the flour, improves suitability for diabetic and low-glycaemic diets, and decreases microbial growth risk, thereby enhancing product stability during storage.

[0038] In an embodiment, the sucrose content is less than 20 g / 100 g flour, preferably less than 18 g / 100 g flour, more preferably less than 15 g / 100 g flour, and most preferably less than 10 g / 100 g flour. In an embodiment, the sucrose content is between 0.1 and 22 g / 100 g flour, preferably between 1 and 20 g / 100 g flour, more preferably between 1 and 15 g / 100 g flour, and most preferably between 2 and 10 g / 100 g flour. Sucrose may be measured by HPLC with refractive index detection or by enzymatic assay kits specific for sucrose. Lower sucrose levels are particularly beneficial because sucrose is a highly fermentable substrate for many spoilage organisms and pathogens; reducing sucrose thus further contributes to extended shelf-life and reduced spoilage. In an embodiment, the glucose content is less than 7 g / 100 g flour, preferably less than 6 g / 100 g flour, more preferably less than 5 g / 100 g flour, and most preferably less than 4 g / 100 g flour. In an embodiment, the glucose content is between 0.1 and 8 g / 100 g flour, preferably between 1 and 7 g / 100 g flour, more preferably between 1 and 5 g / 100 g flour, and most preferably between 1 and 4 g / 100 g flour. Glucose may be measured by HPLC with RI detection, or by enzymatic spectrophotometric glucose oxidase / peroxidase assays. Lower glucose content is desirable because glucose has the highest glycaemic index of the fruit sugars and contributes strongly to postprandial blood sugar spikes. In addition, reducing glucose further limits microbial fermentation and enhances product stability.

[0039] In an embodiment, the fructose content is less than 14 g / 100 g flour, preferably less than 12 g / 100 g flour, more preferably less than 10 g / 100 g flour, and most preferably less than 8 g / 100 g flour. In an embodiment, the fructose content is between 0.1 and 15 g / 100 g flour, preferably between 1 and 14 g / 100 g flour, more preferably between 1 and 10 g / 100 g flour, and most preferably between 2 and 8 g / 100 g flour. Fructose may be measured by HPLC with RI detection or by enzymatic spectrophotometric assays specific for fructose. Lower fructose levels are advantageous because high fructose intake has been linked to metabolic health issues. By reducing fructose, the flour provides a healthier nutritional profile.

[0040] In an embodiment, the fruit flour comprises at least 2 g malic acid per 100 g flour. In an embodiment, the malic acid content is at least 2.5 g / 100 g flour, at least 3 g / 100 g flour, or at least 3.5 g / 100 g flour. In another embodiment, the malic acid content is between 2 and 10 g / 100 g flour, preferably between 2 and 8 g / 100 g flour, and more preferably between 2 and 6 g / 100 g flour. Organic acid content, including malic acid, may be measured by HPLC with UV detection after aqueous extraction. A higher malic acid content is advantageous because organic acids lower the pH of the flour, thereby inhibiting microbial growth, enhancing preservative capacity, and contributing to the characteristic sour-tart flavour that improves sensory quality in food formulations.

[0041] In an embodiment, the protein content of the fruit flour is between 4 and 7% by weight. In an embodiment, the protein content is between 4.5 and 6.5% by weight, preferably between 5 and 6% by weight. In another embodiment, the protein content is at least 4% by weight, at least 5% by weight, or at least 6% by weight. Protein content may be measured by the Kjeldahl method (ISO 1871) or by the Dumas combustion method (ISO 16634-1). Maintaining this protein range is advantageous because it supports the nutritional value of the flour and provides functional benefits such as emulsification, foaming, and binding capacity, thereby improving texturizing properties in bakery and food applications.

[0042] In an embodiment, the fruit flour is further characterized by its amino acid composition. A total of 15 amino acids, including six essential amino acids, were identified and quantified, with a total content of approximately 4-6 g per 100 g dry matter depending on particle size fraction. In particular, flour < 100 pm exhibited a total amino acid content of about 5.38 g / 100 g, whereas flour 100-250 pm contained about 4.24 g / 100 g. Essential amino acids such as isoleucine (1.18-1.80 g / 100 g) and lysine (0.22-0.36 g / 100 g) were present at nutritionally relevant levels. Certain amino acids, such as methionine, arginine, lysine and cysteine, may also contribute to the antioxidant functionality of the flour, thereby reinforcing its preservative and bioactive properties. Furthermore, the balance of amino acids influences the flour's technological behavior, including potential participation in Maillard reactions with reducing sugars during drying, which can affect color development. The reduced sugar content achieved through pressing minimizes such browning, preserving the natural color and improving the applicability of the flour as a clean-label food additive.

[0043] In an embodiment, the fibre content of the fruit flour is between 5 and 10% by weight. In an embodiment, the fibre content is between 6 and 9% by weight, preferably between 7 and 8% by weight. In another embodiment, the fibre content is at least 5% by weight, at least 6% by weight, or at least 7% by weight. Fibre content may be measured by the AOAC enzymatic-gravimetric method (AOAC 985.29 or 991.43) for dietary fibre. A higher fibre content is advantageous because dietary fibre slows sugar absorption, and improves satiety, while also imparting favourable rheological properties such as water-holding capacity, bulk, and textural stability in food compositions.

[0044] In an embodiment, the fruit flour comprises a total phenolic content of at least 100 mg gallic acid equivalents (GAE) per 100 g. In an embodiment, the total phenolic content is at least 150 mg GAE / 100 g, at least 200 mg GAE / 100 g, or at least 250 mg GAE / 100 g. In another embodiment, the phenolic content is between 100 and 800 mg GAE / 100 g, preferably between 150 and 600 mg GAE / 100 g, and more preferably between 200 and 500 mg GAE / 100 g. Total phenolic content may be measured by the Folin-Ciocalteu colorimetric assay using gallic acid as a calibration standard. A higher phenolic content is advantageous because phenolic compounds such as hydroxycinnamic acids and flavonoids act as antioxidants, reduce oxidative stress in food systems, and provide health-promoting bioactivity such as antiinflammatory and cardioprotective effects. In certain embodiments, the fruit flour is further characterised by a specific polyphenol fingerprint, comprising hydroxycinnamic acids such as chlorogenic and neochlorogenic acid, and flavonoids such as rutin, catechin, epicatechin and quercetin derivatives. This profile may be determined by high-performance liquid chromatography (HPLC) with diode-array detection and confirmed by LC-MS / MS. The relative abundance of these compounds contributes to both antioxidant and antimicrobial properties, and provides a unique identity marker for quality control of the flour.

[0045] In an embodiment, the fruit flour exhibits an antioxidant capacity of at least 800 mg Trolox equivalents per 100 g as measured by an ORAC assay. In an embodiment, the antioxidant capacity is at least 1000 mg TE / 100 g, at least 1200 mg TE / 100 g, or at least 1500 mg TE / 100 g. In another embodiment, the antioxidant capacity is between 800 and 2500 mg TE / 100 g, preferably between 1000 and 2000 mg TE / 100 g, and more preferably between 1200 and 1800 mg TE / 100 g. Antioxidant capacity may be determined by the ORAC (oxygen radical absorbance capacity) assay, or alternatively by DPPH or ABTS radical scavenging assays, expressed relative to Trolox standards. Higher antioxidant capacity is advantageous because it extends the shelf life of foods by preventing lipid peroxidation and other oxidative spoilage reactions, while also providing functional health benefits through the neutralisation of reactive oxygen species.

[0046] In an embodiment, the moisture content of the fruit flour is below 5 wt.%. In an embodiment, the moisture content is below 4 wt.%, below 3 wt.%, or below 2 wt.%. In another embodiment, the moisture content is between 0.5 and 5 wt.%, preferably between 1 and 4 wt.%, and more preferably between 2 and 3 wt.%. Moisture content may be determined by oven-drying to constant weight (ISO 712) or by thermogravimetric moisture analysis. A lower moisture content is advantageous because it reduces water availability for microbial growth and enzymatic reactions, thereby increasing storage stability and ensuring longer shelf life of the flour and products containing it. Drying may be achieved using methods such as convective drying, contact / conductive drying, fluidized bed drying, solar drying, microwave drying, vacuum drying, or radiofrequency drying, with the choice of method depending on the desired preservation of bioactive compounds and process efficiency.

[0047] In an embodiment, the fruit flour has a water activity (aw) between 0.20 and 0.40 at 25 °C. In an embodiment, the water activity is between 0.22 and 0.38, preferably between 0.24 and 0.36, and more preferably between 0.25 and 0.35. Water activity may be measured by an aw-meter (hygrometer) at 25 °C. Controlling the water activity within this range is advantageous because it ensures microbiological stability while avoiding excessive dryness that could impair handling, solubility, or textural performance of the flour in food formulations.

[0048] In an embodiment, the fruit flour has a particle size equal to or less than 250 pm. In an embodiment, the particle size is less than 200 pm, less than 150 pm, or less than 100 pm. In another embodiment, the particle size is between 20 and 250 pm, preferably between 50 and 200 pm, and more preferably between 80 and 150 pm. Particle size may be determined by sieve analysis (ISO 3310-1) or laser diffraction granulometry. A smaller particle size is advantageous because it improves dispersibility, homogeneity, and mouthfeel in food products, while also enabling better incorporation into doughs, batters, and beverages without imparting graininess.

[0049] The invention also encompasses the selection of fruit sources and formulations.

[0050] In an embodiment, the fruit flour is obtained from fruits selected from Prunus sp., Malus sp. or Pyrus sp., preferably nectarine, pear, apple or peach. In an embodiment, the fruit flour is obtained specifically from nectarine or peach.

[0051] In an embodiment, the fruit flour is derived from Prunus persica var. nucipersica (nectarine) or Prunus persica (peach). In another embodiment, the flour is derived from different cultivars of nectarine or peach, including both yellow- and white-flesh varieties. The use of nectarine and peach is advantageous because these fruits provide a balanced composition of sugars, organic acids and bioactive compounds, yielding a flour with high antioxidant activity and a characteristic flavour suitable for both sweet and savoury formulations.

[0052] In an embodiment, the fruit flour is derived from a single fruit. In another embodiment, the flour is derived from a mixture of different fruits selected from nectarine, peach, pear or apple. Single-fruit flours are advantageous because they provide a consistent nutritional and physicochemical profile, which simplifies formulation and labelling. Mixed-fruit flours are advantageous because they allow tailoring of flavour, nutritional balance, and functional properties by combining complementary compositions from different fruits.

[0053] In an embodiment, the fruit flour is obtained from combinations of two or more fruits selected from Prunus sp., Malus sp. or Pyrus sp. The choice of fruit source is advantageous because these fruits are naturally rich in phenolic compounds, fibre and organic acids, which contribute to the preservative and antioxidant functionality of the flour, while also ensuring broad consumer acceptance due to their familiar sensory profiles.

[0054] In a second aspect, the invention provides a composition comprising a fruit flour as described herein. In an embodiment, the composition comprises between 1 and 99% by weight of said fruit flour. In another embodiment, the composition comprises between 5 and 80% by weight of fruit flour, preferably between 10 and 60% by weight, and most preferably between 20 and 50% by weight. In an embodiment, the composition comprises between 5 and 60% by weight of fruit flour, preferably between 5 and 50% by weight and most preferably by 5 and 40% by weight. Adjusting the amount of fruit flour in the composition is advantageous because it allows tailoring of functional and nutritional properties: lower percentages enable use as a minor additive for flavour or antioxidant effect, while higher percentages allow the flour to serve as a principal ingredient or base component.

[0055] In an embodiment, the composition maintains microbiological and physicochemical stability during storage. In another embodiment, the composition remains stable for at least three months, preferably at least six months, and most preferably at least twelve months under ambient storage conditions. Stability in this context includes the absence of visible microbial growth, minimal changes in moisture content or water activity, and preservation of sensory qualities such as flavour, colour, and texture. Stability is advantageous because it extends the shelf life of the final product, reduces food waste, and ensures safety and quality for consumers.

[0056] In an embodiment, the composition is a gluten-free flour blend. In another embodiment, the composition is a bakery product, such as bread, biscuits, crackers, or cakes. In another embodiment, the composition is a dairy product, such as yoghurt, cheese spread, or fermented milk. In another embodiment, the composition is a beverage, such as juice, smoothie, or functional drink. In another embodiment, the composition is a cosmetic formulation, such as a face mask, exfoliant, or antioxidant cream. The use of fruit flour in such diverse compositions is advantageous because the flour provides multifunctional benefits, including natural preservation, antioxidant protection, nutritional enrichment, improved textural properties, and clean-label appeal.

[0057] In an embodiment, the flour is combined with other natural functional ingredients, such as plant sterols or omega-3 fatty acids, to generate synergistic formulations for cardiovascular or metabolic health. In such cases, the flour functions both as a bioactive source (antioxidant, antimicrobial) and as a carrier matrix.

[0058] In certain embodiments, the flour is formulated into consumer-ready delivery formats such as sachets, drinkable gels, jellies, or capsules containing the powdered flour. These formats allow precise dosing, ease of consumption, and protection of sensitive bioactives during distribution. In the case of capsules or tablets, protective excipients (e.g., maltodextrin, pectin, or resistant starch) may be added to further stabilise polyphenols.

[0059] In a third aspect, the invention relates to the uses of the fruit flour.

[0060] In an embodiment, the fruit flour as described herein is used as a preservative agent, preferably as a food preservative agent. In another embodiment, the flour is added to food compositions at levels between 0.1 and 20% by weight to extend storage stability. In an embodiment, the flour is added at levels between 1 and 15% by weight. In an embodiment, the flour is added at levels between 2 and 10% by weight. In an embodiment, the flour is added at levels between 3 and 8% by weight. In an embodiment, the flour is added at levels between 0.1 and 10% by weight. In an embodiment, the flour is added at levels between 5 and 20% by weight. The preservative effect may be assessed by challenge testing of inoculated food matrices, wherein the growth of indicator microorganisms is monitored over time. The preservative function of the flour is advantageous because it derives from natural constituents such as organic acids and phenolic compounds, which suppress microbial growth without the need for synthetic additives, thereby providing a cleanlabel alternative. In an embodiment, the preservative activity of the fruit flour is antimicrobial against food pathogens such as Salmonella enterica, Escherichia coll, Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus or Pseudomonas aeruginosa. Antimicrobial activity may be measured by standard microbiological assays, such as agar diffusion (inhibition zones), broth microdilution (minimum inhibitory concentration, MIC), or viable count reduction in model food systems. This antimicrobial effect is advantageous because it improves food safety and reduces reliance on chemical preservatives, thereby meeting regulatory and consumer demands for natural preservation strategies.

[0061] In an embodiment, the fruit flour is used as an antioxidant agent, preferably as a food antioxidant agent. The antioxidant effect may be determined by assays such as oxygen radical absorbance capacity (ORAC), DPPH radical scavenging, FRAP reducing power or ABTS radical cation decolourisation. In another embodiment, the antioxidant capacity of the flour is applied to prevent lipid oxidation in fat-containing foods such as bakery goods or dairy spreads, where efficacy may be monitored by peroxide value (PV) or thiobarbituric acid reactive substances (TBARS) assays. This use is advantageous because oxidation is a major cause of rancidity and sensory deterioration in foods; the natural antioxidant capacity of the flour therefore extends shelf life and maintains product quality.

[0062] In an embodiment, the fruit flour is used as a colouring agent, preferably as a food colouring agent. Colouring performance may be measured by CIE Lab colour space analysis* using a spectrophotometer. In another embodiment, the flour imparts a yellow to orange hue when derived from nectarine or peach, or a light beige to brown tone when derived from apple or pear. This use is advantageous because it allows natural colouring of foods without the need for artificial dyes, thereby increasing consumer acceptance and aligning with clean-label product development.

[0063] In a fourth aspect, the invention provides a method for producing a fruit flour, preferably a nectarine flour. The method comprises the steps of: providing fruits and juicing the fruits; separating liquid juice from solid pomace; pressing the solid pomace to remove residual juice; drying the pressed pomace to a moisture content below 5% by weight; milling the dried pomace to obtain a powder with a particle size less than 1000 pm; and sieving the powder to collect a fraction equal to or less than 250 pm, thereby obtaining the fruit flour. Moisture content may be measured by oven-drying to constant weight (ISO 712), and particle size may be measured by sieve analysis (ISO 3310-1) or laser diffraction granulometry. This method is advantageous because it valorises fruit by-products (pomace), generates a flour with controlled physicochemical characteristics, and preserves bioactive compounds while minimising sugar content. By removing the liquid juice fraction, a substantial proportion of free sugars is eliminated, leading to a flour with reduced simple sugar levels compared to the original fruit. The resulting flour is therefore lower in rapidly available carbohydrates, making it more suitable for applications targeting reduced sugar intake or lower glycaemic response.

[0064] In an embodiment, drying is performed in an oven dryer until constant humidity is reached. Drying endpoints may be assessed by gravimetric moisture analysis. In another embodiment, drying is performed by hot-air drying, vacuum drying, freeze- drying, or infrared drying. The drying step is advantageous because it ensures removal of residual moisture, stabilises the flour against microbial growth, and allows reproducible control of water activity.

[0065] In an embodiment, sieving provides fractions of less than 100 pm and 100-250 pm, both fractions being suitable as fruit flour. Fractionation can be verified by standard sieve analysis or laser particle size distribution measurement. Fractionation by sieving is advantageous because different particle sizes can be selected for specific applications: finer flours (< 100 pm) provide smoother textures and are suitable for beverages and cosmetic formulations, while coarser flours (100-250 pm) offer higher fibre content and are suitable for bakery and gluten-free flour blends.

[0066] In an embodiment, the fruit used in the method is selected from Prunus sp., Malus sp. or Pyrus sp., preferably nectarine, pear, apple or peach. The choice of fruit is advantageous because these species are widely cultivated, rich in bioactive compounds, and yield flours with favourable flavour and functional profiles.

[0067] The disclosure should not be seen in any way restricted to the embodiments described and a person with ordinary skill in the art will foresee many possibilities to modifications thereof. The above-described embodiments are combinable.

[0068] EXAMPLES

[0069] Example 1: Preparation and characterization of a fruit flour 1. Materials and methods

[0070] 1.1 Chemical and reagents

[0071] The present research applied chemical reagents (analytical grade): Acetic acid, Citric acid and hydrochloric acid (HCI, 37%), Ethanol (absolute), distilled water, 2,4,6- Tripyridyl-s-triazine (TPTZ, >98%), ABTS diammonium salt (>98%), Folin-Ciocalteu reagent, sodium carbonate anhydrous (Na2CO3, >99.5%), gallic acid (>98.5%),

[0072] Trolox (>97%) and HPLC grade solvents (water, acetonitrile and methanol, Honeywell).

[0073] 1.2 Sample - Nectarine

[0074] Fresh fruits namely nectarine, pear, apple and peach were harvested (ripening point was not precisely measured) from the Obidos region in the center of Portugal and processed by Granfer - Comercializagao de fruta - Obidos, Lisboa (Portugal), during the spring season. After, fruits were treated according to company's standard operations of quality control for cleaning and triage, those fruits that did not pass the quality control of commercial compliance were separated as non-compliant fruits by categories. Unlike previous behavior, the non-compliant fruits were stored at low temperature in darkness, avoiding sunlight and were transported until Molecule Message (MM) Unipessoal LDA (AgroGrIN Tech®) facilities in Porto, Portugal.

[0075] 1.3 Fruit flour

[0076] The non-compliant fruits were processed according to MM parameters. Briefly, the fruit material was processed through a milling-centrifuge machine (juice machine) to separate the liquid juice and collect the fresh solid pomace (FSP). The FSP was mechanically pressed to remove the excess of liquid juice and then the pressed FSP was carefully dispersed into metallic tries to be dried in a conventional oven dryer until the material reached constant humidity percentage (<5%). The FSP now was identified as dried pomace (DP) and sealed in plastic bags until its further processing, avoiding humidity.

[0077] The DP material was milled by using an impact rotor miller with a base sieve output with aperture size of 1000 pm, the milling process was carried out until the initial coarse nectarine DP reach a fine powder of a particle size of less than 1000 pm. Then this powder was fractionated passing through a mechanical vibrating sieve (Retsch AS 200 Basic), operating at 80% amplitude for 15 min without pulse intervals and equipped with three sieves (stainless steel, 0 200 / 203 mm, wire gauze) of different sizes and one collecting tray, positioned in a descending column form organized from the bigger aperture size (500 pm) on the top followed by 250 pm, 100 pm and in the bottom the collecting tray. Finally, two fractions were collected separately, corresponding to a very fine powder of a particle size of < 100 pm and the other constituted between particles bigger than 100 pm and less-equal than 250 pm. The resultant final fine fractions were called “flour < 100 pm” and flour of “flour 100-250 pm”, corresponding to the fruit flour ingredient. The two flour were collected in hermetic bags and stored until their techno-functional characterization and bioactivity (antioxidant and antimicrobial capacity) for potential applications in food formulation.

[0078] 1.4 Particle Size Distribution by Laser Diffraction (Mastersizer 3000, Malvern Instruments)

[0079] The particle size distribution of the samples was determined using a Mastersizer 3000 laser diffraction analyzer. The instrument was operated in dry dispersion mode under the following conditions: refractive index 1.50, absorption index 0.1, air pressure 1 bar, feed rate 50%, and hopper gap 2 mm. Measurements were performed within an obscuration range of 0.1-10% to ensure accuracy and reproducibility. Data were recorded and processed using the instrument's proprietary software, which applies Mie scattering theory to calculate particle size distribution (Figure 1).

[0080] 1.5 Particle Size Analysis by Sieving (Retsch Analytical Sieve Shaker AS 200 Control)

[0081] Complementary particle size analysis was performed using a Retsch AS 200 Control Analytical Sieve Shaker. A representative sample of 100 g was placed on the sieve stack. The shaker was operated for 1 minute at an amplitude of 2 mm / g. After sieving, the mass fraction retained on each sieve was determined gravimetrically, and the cumulative particle size distribution was calculated.

[0082] 1.6 Proximate characterization of nectarine flour

[0083] The proximate analysis was conducted by the Associagao Centro de Apoio Tecnologico Agroalimentar (CATAA), located in Castelo Branco, Portugal. The tests were conducted to determine the following parameters of nectarine flour: Moisture, Dry matter, Ash, Protein, Lipids, Crude Fiber, and Carbohydrates. All the analysis conducted in triplicates and the results were expressed as a percentage of dry nectarine flour (g / 100 g flour).

[0084] 1.7 Moisture and Dry matter

[0085] A gravimetric method was used, which is based on drying the flour sample at 70 °C (under vacuum) for a period of 4 h until constant weight using an in a convection oven (Binder, VDL 115). The dry matter content was estimated by the difference of mean values of the moisture, [%dry mater = 100 - %Moisture] .

[0086] 1.8 Ash

[0087] Ash was determined by carbon removal of the dried flour to be incinerated in a muffle furnace at approximately 550 ± 25 °C for 24 h (Lenton SAF11 / 1 muffle furnace).

[0088] 1.9 Protein

[0089] The total protein content of the flour was determined using the Kjeldahl method as follows: in an acidic medium (H2SO4), in the presence of a catalyst mixture (Kjeltabs Cu / 3.5), and at high temperature (420 °C), the sample undergoes mineralization, converting organic nitrogen into ammonium ions, which in turn are converted into ammonia by the addition of sodium hydroxide. The ammonia was distilled in a steam stream and collected with boric acid, then titrated with hydrochloric acid (HCI) at a known concentration to quantify total nitrogen (Kjeltec 8400, FOSS). Protein was calculated multiplying the mean value of nitrogen percentage by the conversion factor of 6.25 described for foods, [%Protein = %nitrogen x 6.25].

[0090] 1.10 Lipids

[0091] This determination consisted of hydrolysis with a hydrochloric acid solution (Soxcap, FOSS), followed by filtration and washing. The total fat was then extracted with petroleum ether (Soxtec System 2047, FOSS), and finally the organic solvent was removed by evaporation, drying, and weighing of the remaining resine. 1.11 Total carbohydrates

[0092] The determination of total carbohydrates was calculated in accordance with the guidelines set out in Regulation (EU) No. 1169 / 2011, considering the difference of mean values of the moisture, lipid, protein and ash content, [Total carbohydrates = 100 - %Moisture - %lipids— %Protein -%Ash].

[0093] 1.12 Simple sugars

[0094] The determination of sugars (glucose, fructose, sucrose, lactose, and maltose) was performed with water, followed by centrifugation and removal of interferents in a solid-phase extraction column (SPE-C18, 500 mg 10 mL-1). Then, the quantification of sugars was performed by ion chromatography (ICS-3000, Dionex), with an electrochemical detector and Chromeleon software. A CarboPac PA20 column (3 x 150 mm), a CarboPacGuard pre-column (3 x 30 mm), two mobile phases (200 mM NaOH and 15 mM NaOH), and a flow rate of 0.5 mL / min were used. The results obtained for each sugar are expressed in g / 100 g nectarine flour.

[0095] 1.13 Techno-functional analysis

[0096] 1.13.1 Water absorption capacity and oil absorption capacity

[0097] The water holding capacity and the oil holding capacity were determined following the method proposed by Aziah and Komathi (2009) with slight modification, where 1 g of nectarine flour was mixed with 10 mL of water or 10 mL of sunflower oil, accordingly. The suspensions, both water and oil, were vortexed for 30 s and incubated at 60 °C for 30 min in a water bath. After the rest period, the samples were centrifuged at 1110 rpm for 15 min, the supernatant was carefully removed, and the resultant pellet in the bottom was weighed. The water holding and oil holding capacity results were determined by deducing the weight of the dry sample from the weight of the resultant pellet and then dividing this result by the weight of the initial dry flour sample and expressed as grams per grams of dry weight (g water or oil / g nectarine flour).

[0098] 1.13.2 Emulsifying capacity Emulsifying capacity was determined according to the methodology proposed by Yasumatsu et al. (1972). An initial suspension with concentration of 1% (w / w) of nectarine flour was prepared, 3 mL of flour suspension was mixed with 3 mL of sunflower or soybean oil, accordingly. The suspension was emulsified by using an Ultra-Turrax homogenizer (IKA Ultra-turrax T18, Wilmington, USA) at 9500 rpm for 3 min at room temperature. The mixture was centrifuged at 1100 rpm for 30 min. First, the volume of the emulsified layer was measured. Emulsifying capacity measurements were performed for in triplicate. The emulsifying capacity (%) was expressed as the height of the emulsified layer divided by the total height formed by the emulsifying layer plus water layer as follows: the height of emulsified layer (cm)

[0099] ° / oEC * 100 total height of whole layer (cm)

[0100] 1.14 Color analysis

[0101] For color parameters the CIELAB color space (L* a* b*) was applied, with measurements being performed with a colorimeter (Minolta® Chroma Meter model CR-400), equipped with illuminant D65, to better replicate daylight (Sardao et al., 2021). The L* is the lightness value (that defines black as 0 and white as 100), the a* axis corresponds to the green-red colors (where negative values correspond to green and positive ones to red) and the b* axis corresponds to blue-yellow colors (where negative values correspond to blue and positive ones to yellow). The color was evaluated as a mean of six replicates for the respective flour samples.

[0102] 1.15 Water activity (aw)

[0103] The water activity of the nectarine flour was measured at 25 °C using a Hygrolab meter (Rotronic, Instrument Corporation Inc., Hauppauge, NY, USA) (Goudor et al., 2023). Approximately 10 g of dried nectarine flour, in triplicates, were placed into the plastic cup of the Rotronic hygrolab device and furtherly collocated inside the cup holder equipped with the probe. The reading was taken in between 5-6 min Whitin the guidelines of the manufacturer.

[0104] 1.16 Antioxidant Capacity

[0105] 1.16.1 FRAP - Ferric reducing capacity The ferric reducing ability was determined according to the method of Bautista- Hernandez et al., 2022. The FRAP reagent was prepared by mixing of TPTZ (10 mM) in 40 mM HCI, FeCI3 (20 mM), and Acetate buffer (pH 3.6, 0.3 M) in a ratio (1: 1 : 10). A volume of 290 pL of FRAP reagent was mixed with 10 pL of the sample or standard concentration (Trolox, pg / mL). The reaction mix was incubated in darkness for 15 min, and the absorbance was quantified at 593 nm. The results were expressed as grams equivalents of Trolox per 100 g (g TE / 100 g flour).

[0106] 1.16.2 ABTS - radical scavenging assay

[0107] The ABTS*+ assay was carried out following the methodology proposed by Arnao et al., 2002 with slight modifications. A stock solution (ABTS* + , 7mM; and potassium persulfate, 2.5 mM) was diluted with water until reaching an absorbance of 0.700 ± 0.020 at 734 nm. Then, 20 pL of sample were mixed with 180 pL of ABTS*+ for 5 min in darkness, the absorbance was measured at 734 nm. The standard curve was made with Trolox (25-200 pg / mL). The results were expressed as grams equivalents of Trolox per 100 g (g TE / 100 g flour).

[0108] 1.16.3 DPPH - radical scavenging assay

[0109] The DPPH*+ assay was carried out according to the procedure described by Vilas- Boas et al., (2023). Briefly, 175 pL of DPPH*+ work solution (60 pM) was allowed to react with 25 pL of extract (previously diluted in distilled water) in a 96-well microplate (Nunc™; Thermo Fisher Scientific Inc., USA) for 30 min in darkness. Then, the absorbance was measured at 515 nm (multidetection plate reader Synergy Hl; BioTek Instruments, Winooski, VT, USA), and a blank was taken with distilled water. The inhibition percentage of the sample was calculated using Equation (2), and Trolox was used as a standard to prepare a calibration curve (7.5- 75 mg / mL). The results were expressed as milligrams of Trolox equivalent per 100 g of flour (mg TE / 100 g). Three independent analyses were performed in each triplicate extract obtained for each methodology.

[0110] 1.16.4 ORAC - Oxygen radical absorbance capacity assay

[0111] The ORAC assay was evaluated according to Davalos et al., 2004. The reaction was carried out in phosphate buffer (75 mM, pH 7.4), 20 pL of the sample and 120 pL of fluorescein (116.66 nM) were mixed in a black microplate (Nunc, Denmark) and pre-incubated at 37 °C for 15 min. After, 60 pL of 2,2'- azobis-(2- methylpropionamidine)-dihydrochloride (AAPH) (46,6 mM) was added and then incubated at 40 °C for 137 min with a total of 104 measurements (FlouSTAR OPTIMA fluorimeter, BMG Labtech, Offenburg, Germany) at 458 nm and 520 nm creating a curve. The normalization process englobed the blank curve corresponding to the same assay by multiplying the original data by fluorescence blank, t=0 / fluorescence sample, t=0. Then, the AUC (Area Under the Curve) was calculated with the following equation

[0112] W AUC = 1 + 2 =I°40 where fO is the initial fluorescence average at 0 min and fi is the fluorescence media at time. The AUC of each sample read was calculated by the following formula:

[0113] (2) AUC = AU CAntioxidante— AUCControl

[0114] AUC AUC antioxidant AUC control. The calibration curve was made using Trolox (0.0002 to 0.0016 pmol TE / mL) as an antioxidant standard. The results were expressed as grams equivalents of Trolox per 100 g (g TE / 100 g flour).

[0115] 1.17 Total phenolic content (TPC) and individual profile by HPLC

[0116] The total phenolic content was determined by Folin-Ciocalteu method Singleton and Rossi, 1965. An aliquot of 20 pL of sample and 80 pL of Folin-Ciocalteu reagent were mixed. After that, 100 pL of sodium carbonate (75 g / L) were added to the mix. Then, the mix was vortexed, and the reaction was incubated for 1 h in the dark at room temperature; and the absorbance was measured at 750 nm. The calibration curve was prepared using gallic acid as a standard (0 - 200 pg / mL). The results were expressed as grams equivalents of gallic acid per 100 g (g EGA / 100 g flour).

[0117] 1.18 Identification and quantification of sugars and organic acids by HPLC The chromatographic separation was carried out according to Gomez-Garcia et al., 2022, using a Beckman Coulter HPLC equipment coupled to IR (K-2301) and UV detector (K-2501) (Knauer, Berlin, Germany). The sample (20 pL) was analyzed using an Aminex HPX-87H column (Bio-Rad, Hercules, CA, USA) operated at 40 °C with 5 mM H2SO4 as mobile phase at constant flow of 0.6 mL / min. Data acquisition and analysis were accomplished using Clarity software. The detection of simple sugars and organic acids was obtained by the IR and UV detectors. The peaks from each sample were identified and quantified by comparison of retention time and by using calibration curves of each standard from 1 to 20 g / L of specific sugar and from 0.2 to 2 g / L of specific organic acid.

[0118] 1.19 Amino acid profile

[0119] The nectarine flour extracts (100 pL) were mixed with 100 pL of 6 M HCI into small SPME vials (Sigma-Aldrich, USA). The mixture was vortexed for proper mixing. The pH was adjusted to 3.5 using 10 M NaOH. The solution was transferred to a 10 mL volumetric flask, diluted to the mark with ultra-pure water, and filtered through a 0.22 pm filter. The analytical e the chromatography equipment was equipped with a high-resolution fluorescence detector and autosampler for amino acid detection and quantification was used. The chromatographic separation was performed on a Chromolith® Performance RP18e column (100-4.6 mm, Sigma-Aldrich). An amino- acid calibration curve was created using a 100 mg / L of specific amino acid stock solution in 0.1 M HCI.

[0120] 1.20 Antimicrobial activity

[0121] Distinctive food pathogen and contaminant bacteria were chosen like Salmonella enterica serovar Enteritidis ATCC 13076, Escherichia coll ATCC25922, Staphylococcus aureus ATCC 25923, Bacillus cereus NCTC 2599, Listeria monocytogenes and Pseudomonas aeruginosa. The strains Escherichia coii, Staphylococcus aureus and Pseudomonas aeruginosa are also representative contaminants from cosmetic products usually used as markers as a cosmetic preservative. The minimum inhibitory concentrations (MIC) were determined using a broth microdilution assay, following the standards for antimicrobial susceptibility testing provided by the Clinical and Laboratory Standards Institute (CLSL) For this inhibitory analysis, the nectarine flour extracts were dissolved and homogenized with an ultra-turrax in distilled water at initial concentration of 25% (w / v), then the suspension was centrifuge at 5000 rpm for 15 min. The clarified supernatant then was tested against bacteria at three different concentrations at 10, 30 to 50 mg / mL (1, 3 and 5% w / v, respectively) and sterilized by filtration through a 0.22 pm filter (FriLabo - Maia, Portugal). Each well of a microplate was filled with a total volume of 200 pL containing approximately 5x10^5 CFU / mL of test bacteria and variable concentrations of the nectarine flour extract. The microplate was incubated for 24 h at 37 °C. Bacterial cells viability was read every hour in a UV / VIS microplate reader (Thermo Scientific Multiskan GO) with an optical density of 660 nm. The MIC value correspond to the lowest extract concentration that inhibited detectable bacterial growth. Two sterilized controls were used, the firs one with the medium (no sample nor inoculum) as negative control (C-) and the second with medium and bacteria (no sample) as positive control (C+). All the sample extracts and controls were performed in triplicate.

[0122] 2. Results and discussion

[0123] 2.1. Proximate composition of nectarine flour / powder

[0124] Table 1 indicate the average composition of the nectarine flour. Firstly, the moisture content of the flour always was kept bellow 5% to guarantee stability and preservation, avoiding spoilage from microorganism during storage, the average value was 3.25% lower than compared with Bulgarian nectarine powder ranging from 13.5 to 14.5% at different conditions of drying (42 °C for 8 h), whereas water activity (aw) of both flour were lower ( flour < 100 = 0.39 and flour 100-250 = 0.37) than reported for common flours specially from wheat (0.491-0.619) Marynin et al., 2021. For a commercial flour with a long shelf life at room temperature, the water activity (aw) should be 0.2 up to 0.4 to be considered shelf-stable, being nectarine flour under these values guarantee a microbiology stable product. Carbohydrates as expected were the component in higher amount accounting for 79.83% almost 8% less than Bulgarian nectarine (86.33%), ash content also was lower with 3.51% against 4.87% and lipids (0.60%) were higher than Bulgarian (0.25%). On the other hand, protein (5.6%) and total fiber (7.22%) contents were greater than reported from Bulgarian nectarine, reporting on average 1.98% and 2.13%, respectively (Vasileva et al., 2024). There are reports that also found some variabilities on these components from different varietes of Prunus persica, includign Royal Summer peach flour (Martin-Diana et al., 2025), reporting higher content of protein (6.88%) and fiber (22.50%) and from peach peel fours (Solomakou et al., 2024) where notably presented lower contents (1.14% and 1.31%, respectively). Although, such parameters found on nectarine flour still are bellow than the contents of wheat flour which can vary from 10 to 13% of protein and 10 to 16% of fiber (Atwell, W. A., & Finnie, S. 2016), flours made of fruits could stand out from the conventional ones made of cereals, highlighting the null content of gluten, a type a complex proteins which have been associated with some health issues (Stordal et al., 2025), and also fruit flours could exert and improve bioactive properties such as antioxidant and antimicrobial capacities due to their high content of bioactive compounds like polyphenols, vitamins and organic acids (Mesta-Corral et al., 2024). Therefore, pursuit the richness of the composition of nectarine flour, it could be used to develop functional gluten-free food ingredients to be used totally or partially in mixed food formulation, as alternative ingredients, without modifying the nutrition composition of the final products.

[0125] Table 1. Chemical composition of nectarine flour developed from non-complain fruits.

[0126] Component Nectarine flour

[0127] Minerals (Ash) 3.51 ± 0.11

[0128] Protein* 5.60 ± 0.13

[0129] Fat 0.60 ± 0.06

[0130] Carbohydrates 79.83 ± 0.14

[0131] Simple sugars 44.30 ± 0.19

[0132] Fiber 7.22 ± 0.16

[0133] *Protein may vary due to crop conditions

[0134] 2.2 Techno-functional properties 2.2.1 Water (WAC) and oil (OAC) absorption capacity

[0135] The values of techno-functional properties namely water and oil holding, emulsifying capacity and color of the different nectarine flours (< 100 and 100-250 jim) are present in Figure 1. The water absorption capacity (WAC) reveals the affinity of flours in how is associated with water molecules. The highest value of WAC for nectarine flour 100-250 was 3.06 g / g of flour followed by flour < 100 with 2.53 g / g of flour equally to 306.93 and 252.74% of absorption, respectively, revealing the presence of the high number of hydrophilic groups within complex polysaccharides among cellulose and hemicellulose in the flour but principally pectin, a well know water-soluble polysaccharide present in fruits weakly bound in the cell wall (Patova et al., 2023). In contrast, the highest value registered for oil absorption capacity (OAC) was in flour < 100 with 1.32 g / g of flour equally to 132.44% of absorption this lower value than WAC could be attributed to the low content of lipids in the flour, conducting small interactions with these hydrophobic molecules responsible for oil absorption. These results could be considered lower when compared with reported results from peach peel (WAC = 6.44 mL / g and OAC = 3.97 mL / g) (Martin- Diana et al., 2025), but higher than common flours coming from wheat (WAC = 132.33% and = OAC 141.56%), rice (WAC = 171.53% and OAC = 118.36) and gram (WAC = 181.66% and OAC = 154.43%) (Kakar et al., 2022). Overall, due to the high content of carbohydrates and proteins in nectarine flour tend to evidence a strong hydrogen bonding because of the presence of the polar or charged side chains in the chemical structure of these molecules it is because the high-water absorption. Particle size plays a critical role in gluten-free flour development, significantly affecting its functional properties, and studies have demonstrated that smaller particles enhance the water-holding capacity of flour, improve carbohydrates matrix stability during baking, and shaping the texture.

[0136] 2.2.2 Emulsifying capacity (EC)

[0137] The emulsifying capacity (EC) of the nectarine flour was tested against two types of oils, sunflower and soybean (Figure 2). The values for both oils were very similar accounting with 53.15% (sunflower) and 53.07% (soybean). These values are higher than reported for common flours made of wheat (20.49%), rice (16.87%) and gram (7.73%) (Kakar et al., 2022) as well as higher than lentil (47%) and quinoa (13%) flours, a legume and a cereal, respectively, both rich in proteins and fibers (Badia-Olmos et al., 2024) and even higher with 2.5-times more than in peach peel flour with an EC of 20.99%, which is a fruit in the same family as nectarines (Martin-Diana et al., 2025). These better results found in nectarine flour could attributed to higher content of protein and also probably due to the pectin within the fiber, because in emulsions composed by oil in water, the hydrophobic protein molecules adsorb at the oil-water interface, forming a physical impediment that avoids coalescence and stabilizes layers around oil droplets. The oil droplets are also sterically stabilized by hydrophilic carbohydrate moieties protruding into the aqueous fraction (Medeiros et al., 2019). Thus, these results suggest that the combination of a higher protein and fiber contents with potential pectin domains, all together might improve the emulsifying capacity of the nectarine flour, being capable to stabilize and texturize different food products.

[0138] 2.2.3 CIE L*a*b* color spectra analysis

[0139] Color of food have been always one of the principal characteristics leading to the consumer's acceptance and choice of specific products. Figure 3 contains the visual values of the measured color parameters of the studied nectarine flours, as color itself from products naturally colorful like fruits, it is an important feature to be preserved and kept after processing. The highest values for brightness were found in the nectarine flour of < 100 jim followed by flour of 100-250 jim (L* = 32.28 and 21.96, respectively), whereas the parameter a* associated with the green-red colors showed a value of 4.95 for flour of < 100 jim lower than flour of 100-250 jim with 6.20. As to the value of b* parameter indicated for a blue-yellow-shade color were 10.54 and 7.53, respectively. The values on the color parameters of nectarine flour were lower than peach peel flour (L* = 63.99, a* = 10.46 and b* = 14.62) and specially corn flour (L* = 85.65, a* = 4.09 and b* = 22.41) (Martin-Diana et al., 2025). These higher CIE / _*a*b* parameter on nectarine flour could be attributed to red pigments present in the nectarine fruit such as anthocyanins or carotenoids. In this regard, typical industrial flour made of cereals or seeds are refined and bleached to obtain a very white color, eliminating naturally pigments molecules among carotenoids and polyphenols, for this reason the color preservation is crucial for tailoring made flours to be applied in specific food product formulations, particularly in food and nutraceutical industries targeting more natural ingredients and colorful distinct benefits.

[0140] 2.3 Sugars and organic acids

[0141] Results of soluble sugars and organic acids of nectarine flours are depicted in Figure 4. Three soluble sugars were identified where sucrose was the most representative sugar (17.43 and 15.13 g / 100 g) followed by fructose (10.59 and 8.43 g / 100 g) and then glucose (5.46 and 4.77 g / 100 g) for flour of < 100 jim and 100-250 jim, respectively. On the other hand, five organic acids were identified in both nectarine flours, these acids contribute to the characteristic tangy flavor of nectarine and contribute to the shelf life of the fruits, remarking malic acid (1.95 and 3.16 g / 100 g) was the highest acid detected, followed by succinic (1.08 and 1.77 g / 100 g), citric (1.06 and 1.23 g / 100 g), acetic (0.25 and 0.21 g / 100) g and tartaric (0.07 and 0.09 g / 100 g). Therefore, measuring sugars and organic acids from nectarine flour could allow the identification of important molecules to demonstrate its potential application as clean-label functional ingredient rich in compounds that can exert beneficial capacities such as antimicrobial activity for food formulations, while human health is not compromised. Moreover, as such malic acid was already reported with antimicrobial properties among Listeria monocytogenes, Salmonella Enteritidis and Escherichia coll 0157 :H7 Raybaudi-Massilia et al., 2009

[0142] 2.4 Amino acid profile

[0143] The amino acid composition of nectarine flour was determined, enabling the identification and quantification of 15 amino acids, including six essential amino acids (Table 2). The total amino acid content differed between particle size fractions, with flour < 100 pm containing 5.38 ± 0.47 g / 100 g and flour 100-250 pm containing 4.24 ± 0.37 g / 100 g. Among the essential amino acids, isoleucine (1.18- 1.80 g / 100 g) and lysine (0.22-0.36 g / 100 g) were the most abundant.

[0144] These results indicate that nectarine flour can contribute to dietary amino acid intake, especially when used as a complementary source of protein in gluten-free or fruit-based formulations. In addition to their nutritional relevance, certain amino acids (e.g., methionine, arginine, lysine, cysteine) are known to exert antioxidant effects, which may partly explain the antioxidant activity of the flour. Moreover, the reduced browning observed in the flours may be attributed to the effective removal of soluble sugars during pressing, thereby limiting Maillard reactions between reducing sugars (glucose, fructose) and reactive amino acids such as lysine, glycine, and tryptophan. This preservation of natural color is advantageous for applications in clean-label food products and functional additives.

[0145] Table 2. Amino-acid profile of nectarine flour additive.

[0146] Nectarine flour

[0147] No. Amino Acids (g / 100 g) < 100 100-250

[0148] 1 Aspartic Acid 0.99 ± 0.65 1.18 ± 0.63

[0149] 2 Glutamic Acid 0.4 ± 0.25 0.25 ± 0.14

[0150] 3 Cysteine 0.07 ± 0.05 0.05 ± 0.01 4 Serine 0.21 ± 0.15 0.31 ± 0.03

[0151] 5 Glutamine 0.09 ± 0.02 0.07 ± 0.03

[0152] 6 Glycine 0.16 ± 0.06 0.10 ± 0.05

[0153] 7 Threonine 0.14 ± 0.07 0.09 ± 0.04

[0154] 8 Arginine 0.23 ± 0.14 0.15 ± 0.07

[0155] 9 Alanine 0.17 ± 0.08 0.12 ± 0.06

[0156] 10 Tyrosine 0.11 ± 0.01 0.08 ± 0.02

[0157] 11 Methionine 0.22 ± 0.09 0.15 ± 0.07

[0158] 12 Phenylalanine 0.16 ± 0.01 0.10 ± 0.05

[0159] 13 Isoleucine 1.8 ± 0.09 1.18 ± 0.53

[0160] 14 Leucine 0.22 ± 0.19 0.17 ± 0.08

[0161] 15 Lysine 0.36 ± 0.13 0.22 ± 0.10

[0162] Total 5.38 ± 0.47 4.24 ± 0.37

[0163] 2.5 Total free and bound phenolic (TPC), flavonoids (TFC) contents and antioxidant capacity

[0164] Table 3 and table 4 show the total contents phenolic compounds including flavonoids as well as the antioxidant capacity measured by four types of methodologies of the different nectarine flour extracts. The free TPC values ranged from 108.97 to 176.80 mg GAE / 100 g and TFC from 37.44 to 44.20 mg CE / 100 as well as the bound TPC and TFC ranged from 46.37 to 156.40 mg GAE / 100 g and from 20.52 to 35.47 mg CE / 100 g for both nectarine flour from aqueous and methanolic extracts. Nectarine flour of < 100 was the sample with the highest free TPC content and flour of 100- 250 the highest TFC. The assessment of the total content of both free and bound phenolics and flavonoids in the native nectarine flours displayed the natural advantage and potentialities of integrating fruit flour in food formulations due to the remarkable good TPC, slightly lower within the range of wheat flour (TPC and TFC = 206.20 and 96.60 g / 100 g, respectively (Sharma et al., 2014), which underlines its prospective uses as a rich source of phenolic compounds. These bioactive molecules in free or bound form contribute to the antioxidant capacity, which is associated to reducing oxidative stress and associated chronic diseases. In this regard, nectarine flour exerted antioxidant activity against the tested radicals, reengining from 8.05 to 1755.63 mg TE / 100 g, being ORAC the most inhibited radical, while DPPH exerted the lowest values in all the cases. These values are in concordance with Bulgarian nectarine (DPPH = 594.68 mg TE / 100 g) and peach peel (ORAC = 1459.70 mg TE / 100 g) flours (Vasileva et al., 2024; Martin-Diana et al., 2025). This could be attributed to the natural hydrophilic phenolic compounds present in nectarine fruit which still are retained after drying process and have more affinitive in aqueous environments than in organics. Thus, the potential incorporation of nectarine flour for the development of functional foods not only will increase their antioxidant capacity but also will fulfil the increasing consumer demand for natural antioxidant agents with health-promoting properties, demonstrating its applicability in the development of industrial enriched-food products.

[0165] Table 3. Antioxidant capacity, total free phenolic (TPC) and flavonoids (TFC) contents of nectarine flour.

[0166] Nectarine Flour (mg / 100 g)

[0167] Parameter 100-250 AE 100-250 ME < 100 AE < 100 ME

[0168] FRAP (TE) 137.83 ± 0.88 111.78 ± 1.95 126.61 ± 4.97 160.82 ± 3.56

[0169] ABTS (TE) 23.65 ± 0.72 24.97 ± 0.12 24.46 ± 0.25 24.41 ± 0.58

[0170] DPPH (TE) 9.53 ± 0.35 12.46 ± 0.50 8.05 ± 0.54 12.11 ± 0.42

[0171] ORAC (TE) 832.62 ± 76.83 1242.14 ± 70.82 875.55 ± 66.56 1755.63 ± 84.51

[0172] TPC (GAE) 162.30 ± 18.80 108.97 ± 11.09 176.80 ± 15.91 121.80 ± 2.94

[0173] TFC (CE) 44.20 ± 3.92 37.44 ± 3.51 41.86 ± 4.24 40.68 ± 1.11

[0174] All determinations were carried out in triplicated and mean value ± standard deviation.

[0175] < 100: Nectarine flour less than 100 pm of particle size

[0176] 100-250: Nectarine flour bigger than 100 pm and less equal than 250 pm

[0177] ME: 80% methanolic extract; AE: 100% aqueous extract; TE: Trolox equivalents; GAE:

[0178] Gallic acid equivalents; CE: Catechin equivalents

[0179] Table 4. Antioxidant capacity, total bound phenolic (TPC) and flavonoids (TFC) contents of nectarine flour.

[0180] Nectarine Flour (mg / 100 g)

[0181] Parameter 100-250 AE 100-250 ME < 100 AE < 100 ME

[0182] FRAP (TE) 84.56 ± 20.85 105.44 ± 3.04 56.69 ± 4.48 40.48 ± 2.45

[0183] ABTS (TE) 72.70 ± 8.45 77.68 ± 2.89 54.15 ± 0.09 49.16 ± 2.03

[0184] DPPH (TE) 54.32 ± 2.87 54.90 ± 2.44 47.77 ± 2.58 32.36 ± 1.77

[0185] ORAC (TE) 1277.81 ± 68.93 1237.95 ± 125.62 114.37 ± 191.38 944.02 ± 92.65

[0186] TPC (GAE) 134.82 ± 23.07 156.40 ± 1.61 100.45 ± 0.36 46.37 ± 5.74

[0187] TFC (CE) 33.11 ± 8.80 35.47 ± 0.88 21.86 ± 2.18 20.52 ± 0.65

[0188] All determinations were carried out in triplicated and mean value ± standard deviation. < 100: Nectarine flour of less than 100 pm of particle size 100-250: Nectarine flour of bigger than 100 pm and less equal than 250 pm of particle size

[0189] ME: 80% methanolic extract; AE: 100% aqueous extract; TE: Trolox equivalents; GAE: Gallic acid equivalents; CE: Catechin equivalents

[0190] 2.6 Phenolic profile

[0191] The phenolic profile identified and quantified by HPLC of nectarine flour, underlines the variability in the phenolics composition and concentrations profiling between the samples (Table 5). At least 11 phenolic compounds were identified, being hydroxycinnamic acids and flavonoids the two most prominent families in nectarine flour. Phenolic acid compounds included hydroxycinnamic acid, hydroxybenzoic acids, and derivatives. The hydroxycinnamic acid derivatives included chlorogenic, neochlorogenic, cryptochlorogenic, 1-caeoyl-quinid, dicaffeoylquinic, caffeic, p- coumaric, ferulic, transferulic and isoferulic acids. The hydroxybenzoic acids derivatives included ellagic, hydroxybenzoic, syringic and vanillic acids. Moreover, four classes of flavonoids were detected including avanols, avonols, avanones and dihydrochalcone. Regarding avanols, catechin and epicatechin. Additionally, procyanidin and proanthocyanidins, respectively. As for avonols, hyperoside and rutin. In the same way, quercetin, isoquercetin and myricetin were detected. Also, kaempferol and its typical derivatives, kaempferol-3-o-rutinoside, kaempferol-3-o- galactoside and kaempferol-3-o-glucoside. Other avonols including isorhamnetin and cyanidin were also found in peach and nectarine as reported in the literature. In addition, phlorizin and quercitrin were detected, which are the two well- characterized dihydrochalcone and flavanones commonly found in peach and nectarine fruit. Overall, these the diversity in phenolic compounds composition complemented previous studies on peach and nectarine fruits (Guo et al 2020), in which neochlorogenic, chlorogenic, ferulic, quercetin were the predominant phenolics that had been attributed high antioxidant properties and inhibitory effect of the growth of certain bacteria, and fungi by breaking-down cell membranes, damaging nucleic acids, and interfering with metabolic activities (Suriyaprom et al 2022).

[0192] Table 5: Profile of phenolic compounds found in nectarine flour. Phenolic concentration (mg / 100 g flour)

[0193] AE ME

[0194] N Compound Chemical 100- 100-

[0195] RT o. name Class < 100 250 < 100 250

[0196] Neochlorogenic Hydroxycinnam 9. 4.11± 4.17± 1.98±

[0197] 1 acid ic acids 56 0.05 0.89 1.24 BQL

[0198] 10

[0199] 2 Procyanidin Bl Flavonoid .8 BQL n.d. n.d. n.d.

[0200] Hydroxycinnam 13 8.60± 8.56± 8.31± 8.66±

[0201] 3 Chlorogenic acid ic acids .1 2.04 2.40 0.26 0.33

[0202] Hydroxycinnam 18

[0203] 4 Caffeic acid ic acids .4 n.d. n.d. n.d. n.d.

[0204] Hydroxycinnam 20

[0205] 5 Trans-ferulic acid ic acids .6 n.d. n.d. n.d. n.d.

[0206] Hydroxycinnam 21

[0207] 6 p-coumaric ic acids .4 n.d. n.d. n.d. n.d.

[0208] Hydroxycinnam 23

[0209] 7 Ferulic Acid ic acids .3 n.d. n.d. n.d. n.d.

[0210] 23 6.28± 6.46± 9.40± 10.05±

[0211] 8 Rutin Flavonoid .6 0.13 0.06 0.80 0.35

[0212] Kaempferol-3-O- 25

[0213] 9 glucoside Flavonol .3 BQL BQL BQL BQL

[0214] 1 28

[0215] 0 Quercitrin Flavonoid .4 n.d. n.d. n.d. n.d.

[0216] 1 34

[0217] 1 Quercetin Flavonoid .7 n.d. n.d. BQL BQL

[0218] All determinations were carried out in triplicated and mean value ± standard deviation.

[0219] < 100: Nectarine flour of less than 100 pm of particle size 100-250: Nectarine flour bigger than 100 pm and less equal than 250 pm of particle size

[0220] ME: 80% methanolic extract; AE: 100% aqueous extract; n.d. : non-detected; BQL: Below Quantification Level; RT: Retention Time

[0221] 2.7 Antimicrobial activity against food pathogens The antimicrobial activity of nectarine flour of two different molecular size was evaluated as a potential natural antimicrobial agent with preservative potential for food formulations. Different concentrations (10-50 mg / mL = 1-5% w / v) of the extract were tested against six bacteria, three Gram-negative (Escherichia coli, Salmonella enterica and Pseudomonas aeruginosa) and three Gram-positive (Bacillus cereus, Staphylococcus aureus and Listeria monocytogenes). In fact, Escherichia coli, Salmonella enterica, Bacillus cereus, Staphylococcus aureus and Listeria monocytogenes are food pathogens and Pseudomonas aeruginosa are common food contaminants present naturally in fruit and vegetables, which all of them are the responsible that cause food wastage and spoilage, and can cause serious health issues if such foods are consumed. The results revealed that nectarine flours were capable to inhibit the growth of all the six microorganisms studied, being concentration dependent, at higher concentration of flour extract higher power inhibition. The higher concentration tested of nectarine (50 mg / mL) was the most effective (Table 6), inhibiting more than 50% of growth in almost all the cases and reaching almost up to 80%, for example Salmonella enterica (72.83% to 79.36%) and Staphylococcus aureus (54.37% to 78.10%) were the two most sensitive strains (Figure 5) followed by Bacillus cereus (61.78% to 72.33%) and Escherichia coli (57.81% to 75.77%) (Figure 6). Listeria monocytogenes and Pseudomonas aeruginosa were the two strains with lowest inhibition concentrations, ranging from 19.62% to 60.82% and 43.48% to 71.61%, respectively, (Figure 7). Based on the inhibitory results obtained in this study the extracts made from nectarine flours proved to have relevant capacity to be used as an antimicrobial ingredient with potential to be applied as natural preservative agent to control food-borne pathogenic bacteria.

[0222] Table 6. Inhibition percentage of the antimicrobial capacity of nectarine-based ingredients: i) Flour < 100 mm; ii) 100-250 mm and iii) powder (dried liquid fraction).

[0223] Flour < 100 mm

[0224] S. P. L. B. S.

[0225] Concentratio E. enteric aeruginos monocytogene cereu aureu n coli a a s s s 54.75 ± 17.79 ± ± 35.16 14.34

[0226] 1% (w / w) 7.09 1.49 3.37 -2.67 ± 10.03 ± 3.77 ± 5.10

[0227] 59.12

[0228] 67.34 ± 52.54 ± ± 69.10 44.28

[0229] 3% (w / w) 0.36 1.42 1.17 8.84 ± 21.92 ± 4.25 ± 1.76

[0230] 75.76

[0231] 79.35 ± 43.47 ± ± 72.33 62.41

[0232] 5% (w / w) 1.39 2.71 0.51 30.65 ± 1.45 ± 0.57 ± 3.35

[0233] Flour 100-250 mm

[0234] S. P. L. B. S.

[0235] Concentratio E. enteric aeruginos monocytogene cereu aureu n coli a a s s s

[0236] 44.51

[0237] 56.89 ± 11.13 ± ± 29.78 4.79 ±

[0238] 1% (w / w) 0.66 2.66 2.03 -16.97 ± 3.54 ± 2.61 0.81

[0239] 59.26

[0240] 67.10 ± 59.91 ± ± 64.97 19.18

[0241] 3% (w / w) 1.24 0.78 0.98 38.71 ± 13.05 ± 4.54 ± 2.67

[0242] 57.77

[0243] 77.64 ± 71.61 ± ± 71.64 54.30

[0244] 5% (w / w) 0.76 0.44 2.48 19.64 ± 1.82 ± 0.86 ± 5.06

[0245] Powder

[0246] S. P. L. B. S.

[0247] Concentratio E. enteric aeruginos monocytogene cereu aureu n coli a a s s s

[0248] 12.76

[0249] 63.08 ± 21.52 ± ± 30.26 11.41

[0250] 1% (w / w) 12.70 0.40 4.02 4.07 ± 7.48 ± 1.01 ± 9.17

[0251] 53.19

[0252] 66.32 ± 52.10 ± ± 55.19 52.45

[0253] 3% (w / w) 1.19 1.50 1.63 56.10 ± 21.83 ± 5.09 ± 3.88

[0254] 60.97

[0255] 72.83 ± 60.86 ± ± 61.73 78.05

[0256] 5% (w / w) 0.76 0.89 0.66 60.78 ± 2.22 ± 2.25 ± 2.12 Example 2: Nectarine Flour (<250 pm fraction)

[0257] Objective

[0258] To prepare a fruit flour from non-compliant nectarines and characterise its composition and functional properties.

[0259] Materials and Methods

[0260] Raw material: Non-compliant nectarines (Prunus persica var. nucipersica), harvested in central Portugal. Fruits were rejected for fresh market sale due to irregular size and minor skin defects.

[0261] Pre-treatment: Fruits washed with potable water, stones removed.

[0262] Juicing and pressing: Whole fruits subjected to a centrifugal juicer to separate juice from pomace. Pomace pressed mechanically to remove residual liquid.

[0263] Drying: Pressed pomace spread in stainless-steel trays and oven-dried at 55 °C for 24 h until constant weight (<5% residual moisture).

[0264] Milling: Dried pomace milled using an impact rotor mill (1 mm screen).

[0265] Sieving: Powder fraction collected below 250 pm using a vibrating sieve (Retsch AS 200).

[0266] Analytical methods

[0267] Moisture: Vacuum oven at 70 °C to constant weight.

[0268] Water activity (aw): Hygrolab digital hygrometer at 25 °C.

[0269] Sugars: HPLC with RI detector (Aminex HPX-87H, Bio-Rad).

[0270] Organic acids: HPLC with UV detection at 210 nm.

[0271] Protein : Kjeldahl nitrogen determination (factor 6.25). Fibre: AOAC enzymatic-gravimetric method.

[0272] Phenolics: Folin-Ciocalteu method, expressed as gallic acid equivalents (GAE).

[0273] Antioxidant activity: ORAC assay using fluorescein / AAPH system, expressed as Trolox equivalents (TE).

[0274] Particle size: Laser diffraction (Mastersizer 3000).

[0275] Results

[0276] Composition (per 100 g dry matter):

[0277] Total sugars: 40 g sucrose: 19 g glucose: 7 g fructose: 14 g

[0278] Malic acid: 2.2 g

[0279] Protein : 5.6 g

[0280] Fibre: 7.2 g

[0281] Total phenolics: 160 mg GAE

[0282] Antioxidant capacity (ORAC): 1750 mg TE

[0283] Moisture: 3.8%

[0284] Water activity (aw): 0.32

[0285] Particle size: 80% <200 pm

[0286] Example 3: Nectarine Flour (Fine Fraction < 100 pm) Objective

[0287] To prepare and evaluate a very fine fraction of nectarine flour suitable for beverage and nutraceutical formulations.

[0288] Materials and Methods

[0289] Raw material and pre-treatment: Same nectarine batch as Example 1.

[0290] Processing:

[0291] Pomace dried at 55 °C until <4% moisture.

[0292] Milled as in Example 1.

[0293] Sieved with 100 pm mesh to obtain < 100 pm fraction.

[0294] Analytical methods: As described in Example 1.

[0295] Results

[0296] Composition (per 100 g dry matter):

[0297] Total sugars: 36 g sucrose: 18 g glucose: 6 g fructose: 12 g

[0298] Malic acid: 2.5 g

[0299] Protein : 5.9%

[0300] Fibre: 6.5% Total phenolics: 180 mg GAE

[0301] Antioxidant capacity (ORAC): 2000 mg TE

[0302] Moisture: 3.5% aw: 0.29

[0303] Particle size: 90% <90 pm

[0304] This flour has slightly lower sugar and higher antioxidant values, making it particularly attractive as a preservative and antioxidant agent.

[0305] Example 4: Apple Flour (Malus domestica)

[0306] Source: Non-compliant apples, oven dried, sieved to <250 pm.

[0307] Results:

[0308] Composition (per 100 g flour):

[0309] Total sugars: 38 g sucrose: 12 g glucose: 7 g fructose: 19 g

[0310] Malic acid: 3.2 g

[0311] Protein : 4.8%

[0312] Fibre: 8.1%

[0313] Total phenolics: 130 mg GAE ORAC: 1200 mg TE

[0314] Moisture: 4.0%

[0315] 8w : 0.31

[0316] Particle size: 85% <250 pm

[0317] Example 5: Pear Flour (Pyrus communis)

[0318] Source: Non-compliant pears, dried to 4.5% moisture, sieved <250 pm.

[0319] Composition (per 100 g flour):

[0320] Total sugars: 43 g sucrose: 21 g glucose: 6 g fructose: 16 g

[0321] Malic acid: 2.1 g

[0322] Protein : 4.5%

[0323] Fibre: 6.8%

[0324] Total phenolics: 105 mg GAE

[0325] ORAC: 950 mg TE

[0326] Moisture: 4.5% aw : 0.35

[0327] Example 5: Peach Flour (Prunus persica)

[0328] Source: Non-compliant peaches, dried to 3.6% moisture, sieved <250 pm.

[0329] Composition (per 100 g flour):

[0330] Total sugars: 42 g sucrose: 20 g glucose: 7 g fructose: 15 g

[0331] Malic acid: 2.0 g

[0332] Protein : 5.2%

[0333] Fibre: 7.0%

[0334] Total phenolics: 150 mg GAE

[0335] ORAC: 1350 mg TE

[0336] Moisture: 3.6% aw: 0.28

[0337] Example 6: Gluten-Free Bread Formulation Containing Nectarine Flour Objective

[0338] Goal: To assess the performance of nectarine flour as a natural preservative and texturizing agent in gluten-free baked goods. Materials and Methods

[0339] Base formulation : Rice flour (70%), maize flour (20%), tapioca starch (10%).

[0340] Test formulation: 10 wt.% of the maize flour replaced by nectarine flour (<250 pm fraction, Example 1).

[0341] Other ingredients: Water, sunflower oil, yeast, salt.

[0342] Processing: Standard bread-making protocol with proofing and baking at 200 °C for 30 min.

[0343] Analysis

[0344] Shelf life: Microbial growth monitored over 14 days at room temperature (25 °C).

[0345] Texture profile: Measured using a texture analyser (hardness, springiness).

[0346] Antioxidant stability: Lipid oxidation assessed by TBARS assay.

[0347] Results

[0348] The bread containing nectarine flour exhibited no visible mould after 14 days, whereas control bread showed mold growth by day 10.

[0349] Hardness values were reduced by 15%, indicating softer crumb texture.

[0350] TBARS values were 40% lower in the nectarine flour bread, indicating improved oxidative stability.

[0351] Conclusion

[0352] Nectarine flour acted simultaneously as a natural preservative, texturizer, and antioxidant.

[0353] Example 7: Yoghurt Fortified with Peach Flour Objective

[0354] To evaluate peach flour as an antioxidant and colouring agent in dairy formulations.

[0355] Materials and Methods

[0356] Base yoghurt: Prepared from skimmed cow's milk fermented with standard starter cultures (Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus).

[0357] Test yoghurt: 5 wt.% peach flour (<250 pm fraction, Example 5) added postfermentation.

[0358] Control yoghurt: No flour added.

[0359] Analysis

[0360] Colour stability: CIELAB values measured over 21 days at 4 °C.

[0361] Antioxidant capacity: DPPH radical scavenging assay.

[0362] Microbiological stability: Monitored for spoilage organisms.

[0363] Results

[0364] The peach flour yoghurt showed higher a and b values**, indicating enhanced yellow-orange colour.

[0365] Antioxidant capacity increased by 3-fold compared to control yoghurt.

[0366] Microbial counts remained below detection limits for 21 days, while control yoghurt exhibited minor spoilage at day 18.

[0367] Discussion

[0368] Peach flour provided natural colouring and antioxidant functionality, extending the yoghurt's shelf life. Example 8: Plant-Based Beverage with Apple Flour

[0369] Objective

[0370] To test dispersibility, antioxidant effect, and preservative activity of apple flour in a plant-based beverage.

[0371] Materials and Methods

[0372] Base beverage: Oat-based milk alternative (3% oat flour in water, homogenized).

[0373] Test beverage: Supplemented with 3 wt.% apple flour (<250 pm fraction, Example 3).

[0374] Storage: 4 weeks at 4 °C.

[0375] Analysis

[0376] Sedimentation : Visual and particle size analysis.

[0377] Antioxidant capacity: ORAC assay.

[0378] Microbial load: Total viable counts.

[0379] Results

[0380] Apple flour dispersed uniformly, with no sedimentation after 4 weeks.

[0381] ORAC values of supplemented beverage were double that of control.

[0382] No microbial growth observed after 4 weeks in test beverage, compared to detectable spoilage organisms in the control.

[0383] Discussion Apple flour functioned as a texturizer, antioxidant, and preservative, supporting its use in plant-based beverages

[0384] Example 9: Nutraceutical Capsule with Pear Flour

[0385] Objective

[0386] To illustrate the use of pear flour in dietary supplement formulations.

[0387] Materials and Methods

[0388] Capsule formulation : 400 mg pear flour (<250 pm fraction, Example 4) filled into HPMC capsules.

[0389] Comparative: Placebo capsule containing microcrystalline cellulose.

[0390] Analysis

[0391] Antioxidant capacity: Capsule contents assayed by FRAP.

[0392] Phenolic profile: HPLC quantification of rutin and catechin.

[0393] Stability: Capsules stored at 25 °C, 60% RH for 12 months.

[0394] Results

[0395] Antioxidant activity: 1,200 mg TE / 100 g equivalent.

[0396] Rutin : 6.5 mg / 100 g; catechin: 12.3 mg / 100 g.

[0397] Capsules remained stable (no caking, moisture uptake <0.5%) over 12 months.

[0398] Discussion

[0399] Pear flour in capsule form provided a stable nutraceutical with defined phenolic activity, supporting use as a food antioxidant agent Example 10: Cosmetic Cream Containing Nectarine Flour

[0400] Objective

[0401] To evaluate nectarine flour as a natural preservative and antioxidant in a cosmetic formulation.

[0402] Materials and Methods

[0403] Base formulation : Oil-in-water emulsion containing sunflower oil, emulsifiers, water, and glycerol.

[0404] Test formulation: 2 wt.% nectarine flour (< 100 pm fraction, Example 2) incorporated in aqueous phase.

[0405] Controls:

[0406] Positive control: Cream with 0.2 wt.% synthetic preservative (paraben).

[0407] Negative control: Cream without preservative.

[0408] Analysis

[0409] Microbiological challenge test: Creams inoculated with Staphylococcus aureus, Pseudomonas aeruginosa, and E. coli. Survival monitored over 28 days.

[0410] Oxidative stability: Peroxide value of lipid phase.

[0411] Sensory evaluation: Colour and odour assessed by trained panel.

[0412] Results

[0413] Nectarine flour cream inhibited bacterial growth comparably to the paraben control, with >90% reduction of all tested microbes within 7 days.

[0414] Peroxide values were 50% lower than negative control. Panel noted a pleasant, natural fruity odour and stable yellowish colour.

[0415] Discussion Nectarine flour proved effective as a natural preservative and antioxidant in a cosmetic system

Claims

46CLAIMS1. Fruit flour obtainable from fruits, said flour has a total sugar content less than 45 g / lOOg flour where said total sugar content is measured by the total sucrose, glucose and fructose content.

2. Fruit flour according to claim 1, where said flour has a total sucrose content of less than 22 g / lOOg flour.

3. Fruit flour according to any of the previous claims, where said flour has a total glucose content of less than 8 g / lOOg flour.

4. Fruit flour according to any of the previous claims, where said flour has a total fructose content of less than 15 g / lOOg flour.

5. Fruit flour according to any of the of the previous claims, wherein said fruit flour comprises at least 2 g malic acid per 100 g dry flour.

6. Fruit flour according to any of the of the previous claims, where said fruit flour has a protein content of 4-7% by weight.

7. Fruit flour according to any of the of the previous claims, where said fruit flour has a fiber content of 5-10% by weight.

8. Fruit flour according to any of the previous claims wherein said fruit flour comprises a total phenolic content of at least 100 mg gallic acid equivalents per 100 g, including both free and bound phenolic compounds selected from hydroxycinnamic acids (such as chlorogenic and neochlorogenic acid) and flavonoids (such as rutin and catechin).

9. Fruit flour according to any one of the preceding claims, where said fruit flour exhibits an antioxidant capacity of at least 800 mg Trolox equivalents per 100 g as measured by an ORAC assay.

10. Fruit flour according to any one of the preceding claims, where said fruit flour having a moisture content below 5 wt.%.4711. Fruit flour according to any one of the preceding claims, where said fruit flour having a water activity (aw) between 0.20 and 0.40 at 25°C.

12. Fruit flour according to any one of the preceding claims, where said fruit flour having a particle size equal to or less than 250 pm.

13. Fruit flour according to any of the previous claims, wherein said fruit flour is obtained from fruits selected from Prunus sp., Malus sp. or Pyrus sp., preferably nectarine, pear, apple or peach.

14. Fruit flour according to any of the previous claims wherein said fruit flour is derived from Prunus persica var. nucipersica (nectarin) or Prunus persica (peach).

15. Fruit flour according to any of the previous claims, wherein said fruit flour is is derived from a single fruit sort.

16. Composition comprising a fruit flour according to any of the claims 1 to 15.

17. Composition according to claim 16, wherein said fruit flour is present in an amount of 1 to 99% by weight.

18. Composition according to claim 16 wherein said composition maintains microbiological and physicochemical stability during storage.

19. The composition of claims 16 to 18, which is a gluten-free flour blend, bakery product, dairy product, beverage, or cosmetic formulation.

20. Use of fruit flour as a preservative agent, preferably a food preservative agent, wherein said flour is a flour according to any of the claims 1 to 15.

21. Use according to claim 20, wherein the preservative activity is antimicrobial against food pathogens such as Salmonella enterica, Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, Bacillus cereus, or Pseudomonas aeruginosa.4822. Use of fruit flour as an antioxidant agent, preferably a food antioxidant agent, wherein said flour is a flour according to any of the claims 1-15.

23. Use of fruit flour as a colouring agent, preferably a food colouring agent, wherein said flour is a flour according to any of the claims 1-15.

24. Use of a fruit flour according to any of the claims 20 to 23 wherein said fruit flour is nectarin flour.

25. Method for producing a fruit flour, preferably a nectarine flour, comprising the steps of:(a) providing fruits and juicing fruits;(b) separating liquid juice from solid pomace;(c) pressing the solid pomace to remove residual juice;(d) drying the pressed pomace to a moisture content below 5% by weight;(e) milling the dried pomace to obtain a powder with particle size less than 1000 pm; and(f) sieving the powder to collect fractions less than 100 pm and equal to or less than 250 pm particle size, thereby obtaining the fruit flour.

26. The method of claim 25, wherein drying is performed in an oven dryer until constant humidity is reached.

27. The method of claim 24 or 25, wherein sieving provides fractions of less than 100 pm and 100-250 pm, both fractions being suitable as fruit flour.

28. The method according to any of the claims 24 to 26, wherein said fruit is a fruit chosen from fruits selected from Prunus sp., Malus sp. or Pyrus sp., preferably nectarine, pear, apple or peach.

29. Fruit flour according to any of the claims 1 to 15 wherein said flour is obtained by the method of any of the claims 24 to 27.

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